First I want to explain how many types of IP address are present. There are five classes of IP ranges. They are Class A, Class B, Class C, Class D and Class E. Each class allows for a different range of IP addresses.
Class A 1.0.0.1 to 126.255.255.254 Supports 16 million hosts on each of 127 networks.
Class B 128.1.0.1 to 191.255.255.254 Supports 65,000 hosts on each of 16,000 networks.
Class C 192.0.1.1 to 223.255.254.254 Supports 254 hosts on each of 2 million networks.
Class D 224.0.0.0 to 239.255.255.255 Reserved for multicast groups.
Class E 240.0.0.0 to 254.255.255.254 Reserved.
Among of those five Class C addresses are commonly used for small to mid-size businesses.
Class C is more important for link building as well as Search engines take a close look at the servers hosting your site. To combat spamming, sites on the same server are viewed as being on the same server. Search engines have removed linking power from one site to another if they are on the same class C IP.
In other terms, two sites on the same host will only be as powerful as one. While there is no penalty, there is a determent to their power to help each other.
When conducting your search engine marketing campaign ensure you are perusing links on sites with unique class C IP addresses for maximum promotion power.So while building link for your site take a look so that your link from Class C IP address.